The present invention relates generally to tamper-evident packaging for products, and more particularly to a tamper-evident package comprising a container and cooperating closure which are particularly configured for efficient, high-speed closure application and convenient opening by consumers, while still reliably providing visually discernable evidence of opening.
Tamper-evident packaging is in very widespread use by virtue of the assurance it provides to consumers that contents of the package are fresh and unadulterated. While it is known to provide packages with tamper-evident overwraps, heat-shrinkable films, and like arrangements for showing that a package has been opened, such arrangements undesirably add to the cost of packaging, and complicate high-speed processing. In view of this, packaging arrangements have been developed, particularly closures for containers, which include a tamper-evident feature as part of the closure structure. By way of example, U.S. Pat. Nos. 4,418,828, 4,497,765, and 5,205,426, all hereby incorporated by reference, illustrate tamper-evident plastic closure constructions which have met with widespread acceptance in the marketplace by virtue of their reliable function and economical manufacture, and suitably high-speed application with automated packaging equipment.
Closures illustrated in the above-referenced patents have proven particularly effective for use on containers having carbonated contents, with such closures particularly configured to provide the necessary sealing characteristics for sealing such pressurized contents. For other applications, however, where sealing of pressurized contents is not required, closures can be configured to provide other desirable features. For example, for packaging of non-carbonated beverages, such as isotonic xe2x80x9csport drinksxe2x80x9d, juices, water, and the like, it can be desirable to provide a relatively xe2x80x9clow profilexe2x80x9d closure, that is, a closure having a relatively short height, in comparison to its diameter. It can be particularly desirable to configure such arrangements with so-called xe2x80x9cmulti-startxe2x80x9d thread formations, which include plural helical thread elements which cooperate to effect closure retention and sealing, while permitting closure application and removal with relatively little rotation relative to the associated container.
Many tamper-evident arrangements heretofore known provide tamper-indication attendant to a certain degree of relative rotation between a tamper-evident closure and the associated container. However, for those applications in which use of a multi-start thread is desirable for ease of closure removal and application, tamper-evidence must be provided attendant to such relatively small relative rotation during closure removal. The tamper-evident package of the present invention has been particularly configured to provide reliable tamper-evidence in a construction which can be configured for relatively small opening rotation of a closure with respect to its associated container.
A tamper-evident package embodying the principles of the present invention includes a cooperating plastic closure and container, wherein the neck portion of the container has been particularly configured to provide tamper-indicating cooperation with the associated closure. As will be further described, the closure includes a plurality of circumferentially spaced, inwardly extending flexible projections which cooperate with a plurality of circumferentially spaced ratchet-like locking teeth on the container to provide tamper-evidence during opening of the package. Notably, the arrangement is configured such that tamper-evidence is provided attendant to very little relative rotation of the closure with respect to the container, thus permitting the invention to be configured in a package which promotes easy and convenient application and removal of the closure.
The container of the present tamper-evident package has a neck portion defining an opening, with the container having an external thread formation on the neck portion. The thread formation includes at least one helical thread element, with the presently preferred configuration comprising a plurality of thread elements, sometimes referred to as xe2x80x9cmulti-startxe2x80x9d threads, to permit the package to be opened by very little relative rotation of the associated closure. However, the package can be configured with a single helical thread element, or may be configured with cooperating lug-type thread elements on the container and associated closure.
In accordance with the present invention, the container includes a plurality of circumferentially spaced locking teeth positioned on the neck portion of the container beneath the thread formation. Each of the locking teeth has a generally ratchet tooth-like configuration, and includes a locking surface, and a generally outwardly tapering guide surface, opposite the locking surface, extending from the neck portion to the locking surface. In the preferred embodiment, the locking surface of each locking tooth is generally radially and vertically oriented. Notably, the locking teeth are unevenly circumferentially spaced about the neck portion, with the spacing corresponding to the spacing between the flexible projections on the closure tamper band, or multiples thereof. The disclosed configuration desirably provides tamper-evidence attendant to a small degree of rotation of the closure relative to the container.
The closure of the present tamper-evident package is configured for fitment to the neck portion of the container for closing the opening therein. The closure includes a top wall portion and a depending annular skirt portion having an internal thread formation for mating engagement with the external thread formation on the neck portion of the container. Like the preferred form of the container, the closure preferably includes a multi-start thread formation, including plural helical thread elements, to promote convenient application and removal of the closure.
The closure is configured for tamper-indicating cooperation with the container by the provision of a tamper band depending from and at least partially detachably connected to the skirt portion of the closure by a frangible connection. While the illustrated embodiment of the closure of the present package is configured for complete detachment of the tamper band from the skirt portion, it is within the purview of the present invention that the tamper band remain joined to the skirt portion attendant to closure removal, which can be effected by the provision of a non-fracturable connector element joining the tamper band to the skirt portion.
The tamper band includes an annular band portion, and a plurality of inwardly extending flexible projections each movable about a respective horizontal hinge portion joined to the annular band portion. In the preferred form, the hinge portion of each of the projections is relatively thin, thus promoting high-speed application of the closure to the container with minimal resistance from the tamper band.
At least one of the projections of the tamper band is engageable with at least one of the locking teeth on the container, during removal of the closure from the container, for fracturing the frangible connection to provide visual evidence of opening of the package. Preferably, the present package is configured such that a plurality of the projections on the tamper band are configured to be substantially simultaneously engageable with a like plurality of the locking teeth on the container for fracturing the frangible connection between the tamper band and the skirt portion. The cooperation of a plurality of projections and teeth acts to assure consistent and rapid fracturing of the frangible connection between the tamper band and the skirt portion. In the preferred form, there are a sufficient number of projections on the tamper band, and a sufficient number of locking teeth on the container to fracture the frangible connection before the closure has rotated, relative to the container, no more than about 15 to 20 degrees during closure removal. This assures rapid tamper-indication, as is particularly desirable with a multi-start thread formation which, in the illustrated embodiment, is configured to provide opening attendant to 60 degrees of rotation of the closure relative to the container.
As noted, the locking teeth on the container are unevenly circumferentially spaced about the neck portion of the container to promote interfering engagement between a plurality of the projections and a plurality of the locking teeth. In the illustrated embodiment, the neck portion of the container defines a mold parting line, that is, the line or plane at which the mold halves for the neck portion separate. The container includes a first pair of locking teeth each having the locking surface thereof aligned with the mold parting line. A second pair of locking teeth are positioned at right angles to the first pair of locking teeth, with the region between the locking surface of each of the second teeth and the guide surface of a respective on of the first teeth positioned generally at right angles thereto being free of locking teeth. The container further includes at least one locking tooth positioned in spaced relationship between one of the first pair and one of the second pair of locking teeth. The spacing of this further locking tooth corresponds to the spacing between the flexible projections of same tamper band, or multiples thereof. This preferred configuration can result in uneven circumferential spacing of the further locking tooth, depending upon the number of flexible projections on said tamper band.
Additional features of the present package promote the desired locking, interfering engagement between the projections and the locking teeth during closure removal, as well as high-speed application. In a current embodiment, a diameter of the neck portion of the container at the locking teeth is generally equal to a diameter of the neck portion at the thread formation, contributing to formation of a relatively lightweight container. In contrast, the projections of the closure define an inside diameter, when the projections are in a generally horizontally, inwardly extending orientation, which is greater than the diameters of the neck portion at the external thread formation and of the locking teeth. By this arrangement, excessive engagement of the projections with the thread formation during closure application is avoided, thus facilitating high speed application, and permitting use of application devices such as driven belts, spinning wheels, and the like, as opposed to rotatably-driven capping heads. After application, the projections can assume a generally horizontal, inwardly extending orientation for effecting interfering engagement with the locking teeth.
Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.